904 internals

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wardy

wardy

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I'm up to the stage of getting parts organised to build up my 904 trans.

I've been looking around for days and sent countless emails but thought I'd ask the question here. I have a complete stock trans and I'm after EVERYTHING I need to r&r

My combo is a efi 318ci, 75mm single turbo. Looking to make around the 600hp on e85.

Having had no previous experience with chrysler transmissions. What internal components to people recommend?
Some kits you buy (from tci etc) include clutches, seals. But no bands etc

Some other kits include the bands but no clutches... A bit confusing.

It will be a 75% race car with occasional street duties. So id Rather it shift too hard then not hard enough.

Physically building the trans is no problem, just locating the right parts for the job!

Thanks in advance
Wardy
 
I'd personally go with the alto red clutches & kolene steels for the drums. I did new bushings, rings, thrust washers in mine as well. Transgo TF-2 or TF-3 for the shift kit depending on whether you want an auto shift or full manual. Solid kickdown band is typically preferred as is either a 3.8 or 4.2 lever.

Also the ATSG manual is a help for the build.
 
80fbody said:
I'd personally go with the alto red clutches & kolene steels for the drums. I did new bushings, rings, thrust washers in mine as well. Transgo TF-2 or TF-3 for the shift kit depending on whether you want an auto shift or full manual. Solid kickdown band is typically preferred as is either a 3.8 or 4.2 lever. Also the ATSG manual is a help for the build.
Click to expand...

Thanks for the input!

I've heard a bit about the alto reds and kolene steels.. Will definately look more into that.
Also read something about a wider forward band or something??

The valve body won't be that hard for me to sort out, just after a full manual forward pattern (using a pro stick) was thinking of just buying a tci valve body.

Looks like I may have to include 2 different kits to get what I'm after.

What is the purpose of the different lever (3.8/4.2)?
 
Also do the transgo tf-3 kits have the same shift capabilities as an aftermarket valve body?? They are a lot cheaper
 
Ok here is what I've come up with.. Sources from the cope racing transmissions site..

Race rebuild kit which includes the alto clutches and kolene steels
https://www.coperacingtrans.com/pro...d=422&osCsid=c744f7075f52e59ffa6406431bd5f927

Was thinking a 5.0 lever, as it says it speeds up the 1-2 shifts further? Or would a 4.2 be better?
https://www.coperacingtrans.com/pro...d=115&osCsid=c744f7075f52e59ffa6406431bd5f927

Low reverse band
https://www.coperacingtrans.com/pro...d=386&osCsid=c744f7075f52e59ffa6406431bd5f927

Front band
https://www.coperacingtrans.com/pro...d=388&osCsid=c744f7075f52e59ffa6406431bd5f927

And a TF-3 transgo..

What are people's thoughts?
 
You really do need to get at least the major bushings.
Front drum/stator, pump, tailshaft and possibly a few others like the planetary sungear.
 
No need for the 5.0 lever. 4.2 seems to be a better compromise. Transgo kits are easy to follow & work well. I would use those bands. Those red solid bands are pretty much the best out there for us. New sprag rollers/springs are only a few dollars. I'd replace those too for piece of mind. I also replaced all the thrust washers.
 
At that power level you need really good parts and blueprinted specs and since you say it's a 75% race car I'd go with a manual valve body. I haven't used a Trans-go TF-3 kit so no idea how well it works. If you go with a aftermarket valve body most have a recommended front band lever ratio, use what they say. I suggest tightening up the clutch clearances from the factory specs. I'd shoot for .040 on the rear clutch and .055~.065 on the front clutch. The clutch pack clearance is set by selective thickness snap rings. You also need a multi spring pack for the front clutch to replace single wound factory spring that likes to let go at high power/rpm levels. You also need to tighten up the total end play. Factory specs were extremely loose. Get it as close to .015 as you can so the gear train isn't slapping back and forth. Install good gears in the front pump and blueprint it.

904's came in several different varieties with several changes over the years. Some only used 3 clutch discs and 3 pin planetaries. Others had up to 5 disc clutch packs. At your power level you need 4 pin planetaries and preferably 5 disc clutch packs. You'll find those parts in the 998 and 999 versions (look identical to 904's but have the beefier internals). If you don't have those parts www.wittrans.com sells them reasonable.

I'd also suggest a torque converter with a billet snout as their prone to breaking at higher power levels.

I keep hearing the better 904's are the 72 and up versions but I'm much more versed with 727's so don't quote me on that. Another thing I'm not sure of is how much power the stock input shaft will handle. Maybe someone else can say if it's up to snuff. Hopefully Tony "70aarcuda" will chime in as he's done a lot of 904's
 
72 and newer 904 have a better front servo...

watch out switching to a 5 clutch drum...you need the matching pump as it is machined to clear the 5 disc drum.....you can put 5 disc in a 4 disc front drum by using the thin .061 and .068 steels and clutch disc.....

the multi spring kit replaces the single wound spring in the front clutch pac...at high rpm ( how high I dont know)..the single wound spring becomes unwound and lets the disc slip or drag...the multi spring kit stops this...

904 converter needs a chromemoly hub...no if or butts about it....

use can use the alto disc and kolene steels...i did once...now use stock disc and steels..

need to replace at least the drum bushing...pump bushing and tail shaft bushing....

new hardened pump gears are available from TCS..and A&A ...and probably other places also....

I got 4 904s that are raced...with one spare...and a couple more cores stashed away.....

I would use a manual valve body....JMO.......done rambling...lol
 
Over 6000 RPM , on that single wound spring, Tony. That seems to be the accepted limit. I machine down the pressure plate on the direct clutch to get the correct clearance when putting 5 discs in a 4 disc drum.
 
I wouldn't waste my money on red clutches and Kolene steels.

5 clutches in a 4 clutch front drum (thin clutches)...I use stock replacement raybestos clutches and re-tumbled stock steels
TCS multi spring kit
Tranzact trans brake valve body (if yours is really a race car, forget about that trans-go crap and get a real valve body)
Lever is dependent on your valve body- get whichever the valve body recommends. I have a 5.0 in mine.
Relocate the vent to the back of the case
4 pinion steel planetary for the front atleast...you'll strip out the aluminum there in no time if you don't swap it out.

I have had my trans apart a good handful of times this season with this above setup...everything looked mint

This was in a 3535lb car going 11.20's off a trans brake and LOTS of street miles

If you need help getting the right parts, give Hutch at Hutch Transmissions a call...He'll set you up right and doesn't mark up his prices like alot of the other popular vendors do for these transmissions
 
Turbo Action Cheetah is the only way to go for the VB. Affordable and overall a great peice. You know not to start in 1st gear for burnouts right?
 
Red, alto, kolene, blah blah blah. Just make sure you get good Borg Warner clutches and you'll be fine. Most all that other stuff is for bench racin. I know people buffing the stock steels back out and putting them behind 700 HP with no problem. It's a clutch steel sammich. What's to fail if it's assembled right? Nuthin, that's what.
 
Google TCS Products in Langley BC , get their full race rebuild kit , it has everything including kevlar bands and all the bushings and seals { the rear seal isn't the one with the rubber boot so you have to buy that seperate if you want the one with it }, then add to that their billet front drum ,it comes with a 25 spring return module to replace your stock 3 or 4 spring jobber ,I bought the steel one because the aluminum isn't recommended for street use and the drum is machined to accept extra clutches so you don't have to use just thin ones , the kit includes extra red frictions and Kolene steels so I was able to pack 6 clutches into my front drum and use a couple of the thicker ones in the rear , this is the combo that gave me the correct end play between the packs and the retaining ring , a couple of members have driven my car { OldKimmer and Inertia } , it makes over 500 hp and tq { engine dynoed at 524/527 when it was built } and they will tell you my trans works perfectly . The guys at TCS were happy to take my call while I was building it and answer all the questions that came up while I was doing it .
 
An aftermarket front drum is a total waste of money in a 904...Unless your turning higher rpms then pro stock, they are not prone to the same catastrophic failures as 727's.
 
mshred said:
An aftermarket front drum is a total waste of money in a 904...Unless your turning higher rpms then pro stock, they are not prone to the same catastrophic failures as 727's.
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It's not a waste if you want to add extra clutches the right way instead of sticking skinny ones in that heat up . He said it's a 600+hp race car , by your logic he should just run a stock trans then eh ? My motto is build it right and never have to worry about it if you want to cheap out and risk having to do it twice have at it , my car has been cross country 2 and a half times with no issues in the trans and the people I let drive it will tell you straight up they beat the heck out of it with no signs of problem .
 
cannucky said:
It's not a waste if you want to add extra clutches the right way instead of sticking skinny ones in that heat up . He said it's a 600+hp race car , by your logic he should just run a stock trans then eh ? My motto is build it right and never have to worry about it if you want to cheap out and risk having to do it twice have at it , my car has been cross country 2 and a half times with no issues in the trans and the people I let drive it will tell you straight up they beat the heck out of it with no signs of problem .
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The right way? Ask the many who have put the 5 thins in the front drum of a 904 or 5 thinner frictions in a 727, the transmissions are holding up fine in race applications. I ran 5 thin frictions in my front drum this past season, 11.20's off the brake at 3500lbs, 10.50 on a 150 hit...STOCK THIN clutches and steels, clutches are all in fantastic shape! Trans was out numerous times throughout the season, and all was beauty inside....and on the nitrous, thats well over 600hp! I have over 60 passes on the track with this setup, and even more on the street- mine is driven on the street too...a TON...beaten on....except that street miles aren't going to show **** all on the clutches, WOT passes will be the true test as to their holding capabilities, not cruising along on roadtrips...so with your logic, overbuild and buy race parts for a cruiser?

There are a lot of ways to do things...some people like to spend money to think they did things the "right" way, others know what works and only spend what they need to do it...I researched the hell outta this and picked the brains of various builders before deciding how to build it. Never said your parts are no good, just not needed...I won't be the only one to echo these opinions, but what do I know.
 
mshred said:
The right way? Ask the many who have put the 5 thins in the front drum of a 904 or 5 thinner frictions in a 727, the transmissions are holding up fine in race applications. I ran 5 thin frictions in my front drum this past season, 11.20's off the brake at 3500lbs, 10.50 on a 150 hit...STOCK THIN clutches and steels, clutches are all in fantastic shape! Trans was out numerous times throughout the season, and all was beauty inside....and on the nitrous, thats well over 600hp! I have over 60 passes on the track with this setup, and even more on the street- mine is driven on the street too...a TON...beaten on....except that street miles aren't going to show **** all on the clutches, WOT passes will be the true test as to their holding capabilities, not cruising along on roadtrips...so with your logic, overbuild and buy race parts for a cruiser?

There are a lot of ways to do things...some people like to spend money to think they did things the "right" way, others know what works and only spend what they need to do it...I researched the hell outta this and picked the brains of various builders before deciding how to build it. Never said your parts are no good, just not needed...I won't be the only one to echo these opinions, but what do I know.
Click to expand...

While you can put more frictions and steels, using the thinner parts, it has been said that they don't remove the heat properly.
Had a smart builder show me one time if I'd ever seen a 700r4 with the thin 3-4 steels and frictions that had gotten too hot. Burnt excesively to be kind. He would only use the factory thickness friction and steels as he said his experience with the thinner plates had never been good.
His opinion.

For a perfromance transmission, he'd often use Raybestos "Waffle" plates.
 
I think overdrives build up more heat due to towing or even car trans due to "lugging" the motor. Builds more heat in the converter. Got to keep the trans cool. I temp gauge is key, imo.
 
80fbody said:
I think overdrives build up more heat due to towing or even car trans due to "lugging" the motor. Builds more heat in the converter. Got to keep the trans cool. I temp gauge is key, imo.
Click to expand...

not even towing, just normal driving... our 97 ram will kick into 4th (good) at about 40-45 mph but also kick into lockup (bad) seconds later, then it lugs... I have the big B&M 11x11 plate on it, plan on adding another with my gauge
 
Now all of a sudden we are talking about lockup? lol...whatever, I'll save my money and run faster then those who like to blow it on parts they are going to "cruise"

Good luck OP!
 
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